This application is to continue the work of extensive testing, product refinement and meeting regulatory requirements for the 2-speed manual wheelchair wheel, which has entered final development stages under an existing SBIR Phase II award running until early 2004. The product also incorporates automatic hill holding and down hill assisted braking features. Due to the many unforeseen technical challenges in developing the four new critical technologies required for this product and two more generations of design iteration than originally planned, it will not be possible to accomplish the extensive user (clinical) and safety testing planned under the original Phase II funding. Additionally, it has become apparent that many more tests than those originally planned should be completed (including arm pain reduction testing). This testing program will also indicate further areas of design improvement (product refinement) that should be implemented prior to production. The 2-speed wheels must be manufactured under FDA mandated Good Manufacturing Procedures. This application will also fund the extensive efforts needed to meet these requirements. The successful marketing of this 2-speed manual wheelchair wheel product will provide wheelchair users with significant arm strain reduction, added mobility and control that is available all day (no recharging required), and does not use heavy batteries or other costly electronic technology. Magic Wheels will be moderately priced, will only add a few pounds of weight. Its natural feeling operation is quickly learned and it will easily replace the existing quick release wheels on most manual wheelchairs. This will enable users of existing wheelchairs to upgrade to higher performance without buying a new chair.